Method of manufacturing thin nickel foils



Feb. 15, 1955 P. PAWLYK 2,701,901

METHOD OF MANUFACTURING THIN NICKEL FOILS Filed April 3, 1952 FIG-l INVENTOR PETER PAWLYK ATTORNEYS United States Patent METHOD OF MANUFACTURING THIN NICKEL FOlLS Peter Pawlyli, Dayton, Ohio, assignor to The Commonwealth Engineering Company of Ohio, Dayton, Ohio, a corporation of Ohio Application April 3, 1952, Serial No. 280,273 2 Claims- (Cl. 22-57.4)

This invention relates to nickel foils and to a method of producing the same by means of nickel formation attained by the continuous deposition of nickel from the gaseous state. More particularly, the invention relates to nickel foils attained by the thermal decomposition of nickel carbonyl.

Nickel foils of commerce have been prepared from billets of the metal by mechanical work processes such as rolling and swaging under careful operating condit ons and on accurately machined surfaces. in these operations tensile strains applied to the metal foil as the thickness decreases is very important and accordingly relatively expensive machinery is required for adequate control.

The present invention has for its primary ob ect ive a method of forming nickel foils utilizing relatively simple equipment.

A further objective of the present inventionis to provide a method of obtaining a nickel foil with high purity.

Another objective of the invention is to provide a method from which films of 0.001 inch and upward may be readily made.

These and other allied objectives of the invention are attained by the deposit of nickel from the gaseous state on a moving belt having an oxide surface to which the deposited nickel adheres but poorly. Normally the adhesion between the nickel and a metal surface is relatively good and accordingly it is quite unexpected to find that if the nickel is deposited on a surface having a good oxide coating that the adhesion of the film is such that the film does not lift readily but may be removed from the oxide surface by properly disposed mechanical means.

In the practice of the invention a belt of aluminum having a good aluminum oxide surface film may be subjected to the vapors of gaseous carbonyl, the surface of the belt being heated to cause deposition of nickel on the aluminum oxide. A copper oxide surface and a magnesium oxide surface will also permit the deposition of nickel thereon in such fashion that a nickel film may be removed from the surface by the means and method provided in this description. 3

The attainment of the above noted and other allied objectives will become fully apparent upon reference to the following detailed description and accompanying drawings wherein:

Figure 1 is a schematic representat on of apparatus for the carrying out of the process of invention and mcludes a plating chamber and shoe means for stripping of the nickel foil;

Figure 2 is an enlarged sectional view of the stripping shoe means;

Figure 3 is a cross sectional view taken on lines 3-3 of Figure 1; and I Figure 4 is a schematic view illustrating a novel bar means useful for initiation of the stripping action.

Referring to Figure 1 there is indicated at l a source of a carrier gas which is connected by a conduit 3 having a valve 5 and a gauge 7 to a carburetor 9 conta ning nickel carbonyl. The carburetor 9 is immersed in oil 11 contained in tank 13 provided with a heater 15, thermostat control 17 and a stirrer 19 driven through a belt 21 by motor 23. A carburetor outlet conduit 25 having a ump 27 is adapted to provide a mixture of carrier gas and vaporized carbonyl to chamber 29 as required The above apparatus is described more fully in copending application, Serial No. 250,303, filed October 8, 1951, and assigned to the same assignee as the present invention.

2,701,901 Patented Feb. 15, 1955 "ice- Chamber 29 having walls of insulating material is provided with inlet ports 31, 33 and outlet ports 35, 37, as illustrated, and consequently plating gas may be passed into the chamber to contact both sides of an endless belt 39; decomposed gas and those gases which are not decomposed may be passed from the outlets 35, 37 to conduit 25 for recycling through pump 27 or may be passed to waste through line 41 having valve 42 as desired. Each of the conduits referred to may be suitably provided with heat insulation as required, as understood by one skilled in the art.

Endless belt 39 is mounted over rollers 43, 45, 47, 49 externally of the apparatus and roller 49 is driven through gear box 51 and motor 53 as indicated, although it will be readily understood that any of the rollers may be driven as desired. Preferably the rollers are rubber covered to provide good gripping action and to provide 7 heat insulation for the belt 39.

Internally of the apparatus belt 39 passes over rollers 55, 57, 59, 61, 63, 65. This endless belt 39 consists of aluminum and is provided with an oxide surface which may be attained by exposing the aluminum to the air for a period of time, or where desired the temperature of the auto which the aluminum is exposed may be suitably raised to 80 F. to hasten the oxidation of the surface. Such oxide films are very uniform and provide an excellent contact area for the film to be deposited thereon.

Rollers 57 and 63 are immersed in a liquid such as mercury contained in tanks 67, 69, which liquid serves to prevent the escape of gas from the interior of the system. Solid depending wall portions 71, 73 extend respectively into each tank from wall sections 75, 77.

Extending from heat insulating walls 75, 77 and closely adjacent the rollers 59, 61 are resilient baflies such as shown at 79 in Figure 3. Positioned between the roller 59 and chamber 29 is another set of bafiles 80 (Figure 3), oppositely disposed to the baffies 79. Similar sets of baffies are provided as indicated at 81 in the belt outlet of the chamber. These baffles resist the egress of gas from the system by providing a long flow path, and accordingly under the conditions of operation to be noted hereinafter substantially no gas may escape from the described apparatus.

At the outlet of the system a pair of spring mounted rollers 83, 85 embrace the belt 39 and bear against the nickel coatings and serve as a fulcrum point for the lifting of the coating from the belt. The lifting force is applied by peeling shoes 87, 89 which engage the belt 39 closely and taper upwardly therefrom. Reeling members 95, 97 are provided adjacent each peeling shoe and spring loaded roller assemblies 96, 98 are provided between each shoe and each reeling mechanism in order that the film to be wound on the mechanism may be held firm during its passage. Each reeling mechanism as indicated is driven through a gear box and motor as at 99 and 100.

Heating of the belt 39 is essential to the deposition of nickel from the carbonyl vapors passing into the system and accordingly an induction heating unit 101 supplied from a source of electrical energy (not shown) surrounds the chamber 29.

Considering generally the operation of the apparatus described to carry out the method of invention, it is preferable to initially place U-shaped bars 93, 94 (Figure 4) across the belt 39 in tight fitting relation therewith and to drive belt 39 slowly until the bars 93, 94 are at the outlet end of the plating chamber 29. These bars may be readily adjusted to pass through the resilient bafiles of the conduits and are chosen to be of such a length and material, such as stainless steel, as to withstand the slight flexing required in the passage. With the bars so positioned the temperature of the belt 39 is raised by means of the induction heat unit 101 to a suitable temperature, and a mixture of carbonyl gas and carrier gas is fed into the plating chamber. Exemplary conditions for such operation are set forth in the specific examples listed hereinafter.

With an initial coating of nickel formed on the belt 39 and over the bars 93, 94 the belt is moved slowly until the bars 93, 94 have passed out of the chamber. The bars are then removed from each side of the belt and the nickel film is stripped from the belt therewith. These free ends of nickel film are wound to separate reeling mechanisms and the belt placed into operation. Thereafter the deposit of the nickel and the reeling operation may proceed in substantially automatic fashion.

Examples of the operating conditions of the structure and the method of invention described are as follows:

Example I Belt temperature 375 Carbon dioxide flow 9.44 liters per mm. Carburetor temperature 80 F. Plating time 1 minute. Nickel film thickness 1.5 111118.

Example II Belt temperature 375 Carbon dioxide flow 9.44 liters per mm. Carburetor temperature 80 F. Plating time 5 seconds. Nickel film thickness 0.1 mil.

Example III Belt temperature 300 F. Carbon dioxide flow 1 l tter per mm. Carburetor temperature 55 F. Plating time lmlnute. Nickel film thickness 0.1 mil.

Example I V Belt temperature 400 F. Carbon dioxide flow 5 l ters per min. Carburetor temperature 85 F. Plating time seconds. Nickel film thickness 3 mils.

While the above operating conditions provide most' satisfactory nickel films, it will be understood that films may be formed under the following limiting conditions and in any combination thereof:

Belt temperature range 300-400 Carbon dioxide flow 0.5 to 20 liters per minute.

Carburetor temperature range 32 to 100 F.

Satisfactory belt speeds adjusted to other conditions of operation mafyifary from 2.0 to feet per minute, and chamber lengths may vary from about 3 feet to about 20 feet. Other carrier gases such as nitrogen, and so forth, may be employed in the practice of the invention as may be understood by one skilled in the art.

' It will be understood that this invention is susceptible to modification in order to adapt it to different usages and conditions and accordingly, it is desired to comprehend such modifications within this invention as may fall within the scope of the appended claims.

Iclaim:

1. A method of producing nickel metal foil by thermal decomposition of nickel carbonyl which comprises the steps of providing a closed gaseous metal plating chamber, continuously moving an endless metal belt through said chamber, oxidizing the surface of said endless metal belt by subjecting the same to a heated oxidizing atmosphere, removing oxygen from the plating chamber by passing inert gas therethrough, thereafter contacting said moving oxidized belt surface with heatdecomposable gaseous nickel carbonyl, raising the temperature of said endless moving metal belt to between about 300 to 400 F. and circulating said heat-decomposable gaseous nickel carbonyl in contact therewith to cause the gaseous metal compound to decompose and deposit nickel metal onto the oxidized metal belt surface as. a thin metal film, and stripping the thus deposited nickel metal film from the oxidized metal belt as a continuous sheet of nickel metal foil.

2. A method of producing nickel metal foil by thermal decomposition of nickel carbonyl which comprises the steps of providing a closed gaseous metal plating chamber, continuously moving an endless metal belt through said chamber, oxidizing the surface of said endless metal belt by subjecting the same to a heated oxidizing atmosphere, removing oxygen from the plating chamber by passing inert gas therethrough, thereafter contacting said moving oxidized metal belt surface with a gaseous mixture consisting of heat-decomposable gaseous nickel carbonyl and carbon dioxide, raising the temperature of said endless moving metal belt to between about 300 to 400 F. and circulating said heat-decomposable gaseous nickel carbonyl in contact therewith to cause the gaseous metal compound to decompose and deposit nickel metal onto the oxidized metal belt surface as a thin metal film, and stripping the thus deposited nickel metal film from the oxidized metal belt as a continuous sheet of nickel metal foil.

References Cited in the file of this patent UNITED STATES PATENTS 2,344,138 Drummond Mar. 14, 1944 2,375,211 Brennan May 8, 1945 2,382,432 McManus et al Aug. 14, 1945 2,450,428 Hazelett Oct. 5, 1948 2,598,344 Brennan May 27, 1952 

1. A METHOD OF PRODUCING NICKEL METAL FOIL BY THERMAL DECOMPOSITION OF NICKEL CARBONYL WHICH COMPRISES THE STEPS OF PROVIDING A CLOSED GASEOUS METAL PLATING CHAMBER, CONTINUOUSLY MOVING AN ENDLESS METAL BELT THROUGH SAID CHAMBER, OXIDIZING THE SURFACE OF SAID ENDLESS METAL BELT OF SUBJECTING THE SAME TO A HEATED OXIDIZING CHAMBER ATMOSPHERE, REMOVING OXYGEN FROM THE PLATING CHAMBER BY PASSING INERT GAS THERETHROUGH, THEREAFTER CONTACTING SAID MOVING OXIDIZED BELT SURFACE WITH HEATDECOMPOSABLE GASEOUS NICKEL CARBONYL, RAISING THE TEMPERATURE OF SAID ENDLESS MOVING METAL BELT TO BETWEEN ABOUT 300 TO 400* F. AND CIRCULATING SAID HEAT-DECOMPOSABLE GASEOUS NICKEL CARBONYL IN CONTACT THEREWITH TO CAUSE THE GASEOUS METAL COMPOUND TO DECOMPOSE AND DEPOSIT NICKEL METAL ONTO THE OXIDIZED METAL BELT SURFACE AS A THIN METAL FILM, AND STRIPPING THE THUS DEPOSITED NICKEL METAL FILM FROM THE OXIDIZED METAL BELT AS A CONTINUOUS SHEET OF NICKEL METAL FOIL. 